Different Classes of Upanishads

The ancient Upanishads, i.e. those which occupy a place in the
Samhitâs, Brâhmanas, and Âranyakas, must be, if we follow the
chronology which at present is commonly, though, it may be,
provisionally only, received by Sanskrit scholars, older than 600 B.C.,
i.e. anterior to the rise of Buddhism. As to other Upanishads, and
their number is very large, which either stand by themselves, or which
are ascribed to the Atharva-veda, it is extremely difficult to fix
their age. Some of them are, no doubt, quite modern, for mention is
made even of an Allah-upanishad; but others may claim a far higher
antiquity than is generally assigned to them on internal evidence. I
shall only mention that the name of Atharvasiras, an Upanishad
generally assigned to a very modern date, is quoted in the Sûtras of
Gautama and Baudhâyana[32];
that the Svetâsvatara-upanishad, or the Svetâsvataranâm
Mantropanishad, though bearing many notes of later periods of thought,
is quoted by Sankara in his commentary on the Vedânta-sûtras[33]; while
the Nrisimhottaratâpanîya-upanishad forms part of the twelve Upanishads
explained by Vidyâranya in his Sarvopanishad-arthânubhûti-prakâsa. The
Upanishads comprehended in that work are:

The number of Upanishads translated by Dârâ Shukoh amounts to 50;
their number, as given in the Mahâvâkyamuktâvalî and in the
Muktikâ-upanishad, is 108[35]. Professor Weber thinks that their
number, so far as we know at present, may be reckoned at 235[36]. In
order, however, to arrive at so high a number, every title of an
Upanishad would have to be counted separately, while in several cases
it is clearly the same Upanishad which is quoted under different names.
In an alphabetical list which I published in 1855 (Zeitschrift der
Deutschen Morgenländischen Gesellschaft XIX, 137-158), the number of
real Upanishads reached 149. To that number Dr. Burnell[37] in his
Catalogue
(p. 59) added 5, Professor Haug (Brahma und die Brahmanen) 16,
making a sum total of 170. New names, however, are constantly being
added in the catalogues of MSS. published by Bühler, Kielhorn, Burnell,
Rajendralal Mitra, and others, and I shall reserve therefore a more
complete list of Upanishads for a later volume.

Though it is easy to see that these Upanishads belong to very
different periods of Indian thought, any attempt to fix their relative
age seems to me for the present almost hopeless. No one can doubt that
the Upanishads which have had a place assigned to them in the Samhitâs,
Brâhmanas, and Âranyakas are the oldest. Next to these we can draw a
line to include the Upanishads clearly referred to in the
Vedânta-sûtras, or explained and quoted by Sankara, by Sâyana, and
other more modern commentators. We can distinguish Upanishads in prose
from Upanishads in mixed prose and verse, and again Upanishads in
archaic verse from Upanishads in regular and continuous Anushtubh
Slokas. We can also class them according to their subjects, and, at
last, according to the sects to which they belong. But beyond this it
is hardly safe to venture at present. Attempts have been made by
Professor Weber and M. Regnaud to fix in each class the relative age of
certain Upanishads, and I do not deny to their arguments, even where
they conflict with each other, considerable weight in forming a
preliminary judgment. But I know of hardy any argument which is really
convincing, or which could not be met by counter arguments equally
strong. Simplicity may be a sign of antiquity, but it is not so always,
for what seems simple, may be the result of abbreviation. One Upanishad
may give the correct, another an evidently corrupt reading, yet it does
not follow that the correct reading may not be the result of an
emendation. It is quite clear that a large mass of traditional
Upanishads must have existed before they assumed their present form.
Where two or three or four Upanishads contain the same story, told
almost in the same words, they are not always copied from one another,
but they have been settled independently, in different localities, by
different teachers, it may be, for different purposes. Lastly, the
influence of Sâkhâs or schools may have told more or less on certain
Upanishads. Thus the Maitrâyanîya-upanishad, as we now possess it,
shows a number of irregular forms which even the commentator can
account for only as peculiarities of the Maitrâyanîya-sâkha[38]. That
Upanishad, as it has come down to us, is full of what we should call
clear indications of a modern and corrupt age. It contains in VI, 37, a
sloka from the Mânava-dharma-sâstra, which startled even the
commentator, but is explained away by him as possibly found in another
Sâkhâ, and borrowed from there by Manu. It contains corruptions of easy
words which one would have thought must have been familiar to every
student. Thus instead of the passage as found in the
Khândogya-upanishad VIII, 7, 1, ya âtmâpahatapâpmâ vigaro vimrityur
visoko 'vigighatso 'pipâsah, &c., the text of the
Maitrâyanîya-upanishad (VII, 7) reads, âtmâpahatapâpmâ vigaro vimrityur
visoko 'vikikitso 'vipâsah. But here again the commentator explains
that another Sâkhâ reads 'vigighatsa, and that avipâsa is to be
explained by means of a change of letters as apipâsa. Corruptions,
therefore, or modern elements which are found in one Upanishad, as
handed down in one Sâkhâ, do not prove that the same existed in other
Sâkhâs, or that they were found in the original text.

All these questions have to be taken into account before we can
venture to give a final judgment on the relative age of Upanishads
which belong to one and the same class. I know of no problem which
offers so many similarities with the one before us as that of the
relative age of the four Gospels. All the difficulties which occur in
the Upanishads occur here, and no critical student who knows the
difficulties that have to be encountered in determining the relative
age of the four Gospels, will feel inclined, in the present state of
Vedic scholarship, to speak with confidence on the relative age of the
ancient Upanishads.

[34] One misses the Îsâ or Îsâvâsya-upanishad in this list. The
Upanishads chiefly studied in Bengal are the Brihad-âranyaka, Aitareya,
Khândogya, Taittirîya, Îsâ, Kena, Katha, Prasna, Mundaka, and Mândûkya,
to which should be added the Svetâsvatara. M.M., History of Ancient
Sanskrit Literature, p.325.

[35] Dr. Burnell thinks that this is an artificial computation, 108
being a sacred number in Southern India. See Kielhorn in Gough's Papers
on Ancient Sanskrit Literature, p. 193.

[38] They are generally explained as khândasa, but in one place
(Maitr. Up. II, 4) the commentator treats such irregularities as
etakkhâkhâsanketapâthah, a reading peculiar to the Maitrâyanîya school.
Some learned remarks on this point may be seen in an article by Dr. L.
Schroeder, Über die Maitrâyanî Samhitâ.